The present invention pertains to the field of portable processing systems. More particularly, the present invention relates to techniques for improving the communications capabilities of portable processing systems.
Portable processing systems of. various different types are commonly available to consumers today. Examples of such systems are notebook computers, personal information managers (PIMs), and personal digital assistants (PDAs), and new varieties of portable processing systems are continuously emerging. Such systems are popular because they provide their users with great convenience and flexibility in comparison to conventional desktop systems. There are many situations in which a user of a portable processing system may have a need to access data that is stored in some remote processing system. For example, the user may wish to access an electronic mail (e-mail) account maintained by an on-line service provider, to view a site on the World Wide Web, or to download a file from another computer. Unfortunately, conventional portable processing systems such as those mentioned above generally lack the ability to maintain a constant network connection when they are operated in a truly xe2x80x9cmobilexe2x80x9d manner, i.e., when the user does not have access to a physical (xe2x80x9cwirelinexe2x80x9d) network connection or a power outlet.
One reason for this shortcoming is that wireless modems, which are used in many portable processing systems to make network connections in the absence of a wireline connection, typically rely upon the power supply of the portable processing system. When the system is operating on battery power, such as when traveling in a vehicle, the modem""s dependence upon the system""s battery limits the on-line time that is available to the user. In order to avoid having to constantly recharge the battery, a mobile user might power up the computer and log on to the Internet only briefly once or twice a day, to read and send electronic mail or to perform other on-line functions. Or, notwithstanding the power consumption problem, it may simply be inconvenient for a user to power up the computer more than once or twice a day. Thus, mobile users today generally function in a xe2x80x9cpullxe2x80x9d mode; that is, they access the network and download data when they can. The rest of the time, they are essentially cut off from receiving potentially vital, time-critical information. Such data may be obsolete by the time the user is able to establish a network connection and download it.
For many people, such as business travelers who require constant access to their electronic mail and other network services, this manner of use can be inconvenient if not unacceptable. Therefore, what is needed is a technique for enabling a portable processing system to have a constant data link to other systems, so that the user can always receive time-critical data in a timely manner.
The present invention includes a portable processing system which includes two communications units for providing data communication with a remote device at different data rates. A first communication unit provides data communication with a remote device at a first data rate. A second communication unit provides bi-directional data communication with a remote device at a second data rate that is substantially higher than the first data rate. The first communication unit is used to control activation of the second communication unit. Other features of the present invention will be apparent from the accompanying drawings and from the detailed description which follows.